In many spark-ignition, direct-injection, and internal combustion engines, a fuel injection valve and a spark plug are positioned adjacent to each other around the center of each combustion chamber in order to provide an optimum fuel-air mixture or combustivity. With such an arrangement, the density of the fuel is relatively great at the discharge electrodes of the spark plug, thereby causing problems such as shortening the life of the spark plugs due to smoldering of their electrodes, or the generation of smoke due to ignition failure.